The effects of thermal treatments in air and in N2/Ar atmospheres on H2 permeation of self-supported 5 and 10 μm Pd/23 wt% Ag membranes prepared by magnetron sputtering were investigated. After hydrogen flux stabilization at 300C, the membranes were annealed in air at 300C or in N2/Ar at 300/400/450C for 4 days and then tested for hydrogen permeation at 300C. Air treatment generally induced improved permeation for all thicknesses. For the treatments in N2/Ar, permeability generally depends on the heat treatment temperatures and on the thickness of the membranes. In particular, hydrogen permeation was improved for treatment temperature of 450C, but reduced for 400C and below. An average permeability of 2.61 ± 0.4 mol/(m s Pa0.5) for permeation measurements at 300C before heat treatment and an apparent activation energy of about 7kJ/mol obtained in the range of 300 to 450C for N2/Ar treated membranes were comparable to some of the values in the literature. Substantial permeance difference was observed for measurements at 300 to 450C between the membranes heat treated in air at 300C and in N2/Ar at 450C. The measured permeance between 300 and 450C for the 10-μm membranes heat treated in air at 300C remains practically unchanged, i.e. Ea ≈ 0.

Effects of Thermal Activation on Hydrogen Permeation Properties of Thin, Self-Supported Pd/Ag Membranes. W.M.Tucho, H.J.Venvik, M.Stange, J.C.Walmsley, R.Holmestad, R.Bredesen: Separation and Purification Technology, 2009, 68[3], 403-10